The long-term objectives will elucidate the structure and functional properties of platelet activating factor (PAF). Since we have recently demonstrated that the structure of PAF is acetyl glyceryl ether phosphorylcholine (AGEPC, 1-0-hexadecyl/octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, M.W. 523 and 551) and have synthesized AGEPC, the following investigations will be conducted. Structurally defined AGEPC analogues will be synthesized to evaluate structure function relationships (rabbit and human platelet and neutrophil stimulation, vasoactive and smooth muscle contracting properties, intravascular and cardiovascular-pulmonary alterations) and hopefully find an analogue(s) that will antagonize the native AGEPC molecule. Structure-proof analysis will be accomplished upon PAF produced by human neutrophils and possibly other cell types such as the basophil, mast cell or pulmonary alveolar macrophage. The specific pathway(s) for the synthesis of PAF by stimulated human neutrophils will be assessed. Other biological activities of AGEPC that have not yet been reported or examined will be explored. Studies will be pursued vigorously to elucidate the primary and secondary mediator effects of AGEPC which, if not appropriately controlled, may result in a variety of acute and chronic inflammatory, allergic and physiologic reactions leading to severe cardiovascular and pulmonary alterations and tissue injury.